Squeeze coil spring and current transfer means

ABSTRACT

A resilient pressure device between the surfaces of two members comprising a coil spring the axis of which extends parallel to the surfaces of the members; the spring is thus compressed in a direction transverse to its axis. The turns of the spring provide a plurality of pressure points, at least one to a turn, against the adjacent surfaces. The members may slide with respect to each other, either rolling the spring or sliding with respect to the turns of the spring while pressure is maintained. Where the members and the spring are electrically conductive, a constant electrical current transfer is obtained. When current is to be transferred from a terminal to a current carrying member or shaft, the bearing for the shaft in the terminal, or the shaft, may carry such a spring with the axis of the spring spirally wound in the bearing or on the shaft, or a plurality of loops of spring may be used.

United States Patent [191 Wilson [451 Feb. 19, 1974 SQUEEZE COIL SPRING AND CURRENT TRANSFER MEANS [75] Inventor: George A. Wilson, Pineville, Pa.

[73] Assignee: lTE Imperial Corporation, Spring House, Pa.

[22] Filed: Jan. 2, 1973 [21] Appl. No.: 320,086

Primary ExaminerGeo. Larkin M Attorney, Agent, or FirmOstrolenk, Faber, Gerb &

Soffen two members comprising a coil spring the axis of which extends parallel to the surfaces of the members; the spring is thus compressed in a direction transverse to its axis. The turns of the spring provide a plurality of pressure points, at least one to a turn, against theadjacent surfaces. The members may .slide with respect to each other, either rolling the spring or sliding with respect to the turns of the spring while pressure is maintained. Where the members and the spring are electrically conductive, a constant electrical current transfer is obtained. When current is to be transferred from a terminal to a current carrying member or shaft, the bearing for the shaft in the terminal, or the shaft, may carry such a spring with the axis of the spring spirally wound in the bearing or on the shaft, or a plurality of loops of spring may be used.

12 Claims, 13 Drawing Figures SQUEEZE COIL SPRING AND CURRENT TRANSFER MEANS This invention relates to the utilization of a coil spring for current transfer as well as the utilization thereof as a compression spring type of interconnection between two adjacent surfaces.

The invention contemplates'that the coil spring will be used in such manner that the longitudinal axis thereof around which the spring is coiled is essentially parallel to the two surfaces between which it is located. Consequently, in contrast to the prior utilization of spring in which the ends of the spring are connected in order to provide a resilient relationship between two elements, in the present invention the coils or turns of the spring are in contact with the adjacent surfaces. Therefore the coil spring is for all intents and purposes a squeeze coil spring which can be close wound or open wound, of any length, either round, oval or irregular or even rectangular in shape. It can be loose ended between a pair of flat plates or wrapped around a mandrel of any shape and may therefore cooperate with any appropriate surface. It can be used for mechanical load or for electrical current transfer or both and in either a rolling, sliding or static mode.

. When used for current transfer each turn of the coil spring, squeezed between two surfaces between which current is to be transferred, presents contact points against each surface. Therefore where the coil spring consists of multiple turns there is a corresponding number of multiple contactpoints against each of the surfaces against which it is pressed.

Where the coil spring is placed between two surfaces which move parallel to but slidingly with respect to each other the coil spring may be arranged so that its main axis is transverse to the direction of sliding movement. Consequently the coil spring would tend to roll with the relative motion of the surfaces while nevertheless providing the multiple contact points with respect to each of the surfaces while at the same time providing appropriate predetermined resilient resistance to pressure between the two surfaces.

Where the coil spring is placed so that its principal axis is parallel to the direction of relative movement then it will not roll on relative movement of the two surfaces but will nevertheless provide sliding resilient resistance to pressure between the two surfaces and, where current transfer is desired between the two surfaces, will'prov'ide as above pointed out multiple contact points between the two surfaces.

As previously mentioned the coil spring may be a single loop where the two surfaces are approximately circular or may be a continuous spiral of loops in which the continuous spiral itself is formed from a coil spring .so that each run of the spiral has a multiple number of It is therefore the primary object of the present in vention to provide a coil spring which will not only act to provide resilient resistance to load bearing stresses between two relatively movable surfaces but will also, because the coil spring is arranged so that the principal axis on which the spring is coiled is parallel to the surfaces with respect to which it is located, provide multiple resilient pressure points on each of the two parallel surfaces and therefore provide as well multiple current transfer points between the two surfaces.

The foregoing and other objects of this invention will become apparent in the following description and drawings in which:

FIG. 1 is a schematic view showing a novel coil spring of the present invention in its longitudinal elevation between two relatively moving surfaces.

FIG. 2 is a view similar to that of FIG. 1 taken from line 2-2 of FIG. 1 showingthe utilization of a coil spring of the type shown in FIG. 1 where however the relative movement of the two surfaces between which it is located is at right angles to the relative movement shown in FIG. 1 whereby the coil spring provides either rolling or sliding relationship between the two surfaces in contrast to the showing in FIG. 1 where because of the direction of relative movement only a sliding relationship is provided.

FIG. 3 is a view corresponding to that of FIG. 1 in which the two relatively sliding surfaces have been moved closer to each other than-shown in FIG. 1 in which greater pressure is exerted between the turns of the coil spring and the two sliding surfaces.

FIG. 4 is a view taken from line 4-4 of FIG. 3 showing the relationship of the two relatively movable sur facesand the compressed spring to each other; however where one of the plates moves in a direction-indicated by the arrows in FIG. 4 the relative motion may also produce a rolling motion of the spring.

FIG. 5 is a view corresponding to that of FIG. 3 showing the coil spring resilient bearing and current transfer arrangement more greatly compressed.

FIG. 6 is a view corresponding to FIG. 5 taken on line 6-6 of FIG. 5 showing a relationship similar to that previously described in FIGS. 2 and 4.

FIG. 7 is a view corresponding to those of FIGS. 1, Sand 5'showing a compression arrangement approximately the same as that shown in FIG. 5 but with the plates having begun to move in an opposite relative direction with respect to the relative direction of FIG. 5.

FIG. 8 is a view taken from line 88 of FIG. 7 looking in the direction of the arrows and showing the relationship between the plates and the spring similar to that previously described in connection with FIGS. 2, 4 and 6.

FIG. 9 is a view of a current transfer unit in which a moving conductor is moved with respect to a terminal utilizing the coil spring arrangement of the present invention.

FIG. 10 is a view in perspective of a spirally arranged spring in which each loop of the spiral comprises a series of spring coils which may be used in the construc- FIG. 13 is a view in perspective of a straight spring comprising a spiral arrangement on a substantially longitudinal axis in which the spiral itself is a coiled spring and therefore shows a structure such as that illustrated in FIGS. 1 to 8.

Referring now to the FIGS. there is shown in FIGS. 1 and 2 the spirally coiled spring 20 of the present invention placed between two flat plates 21 and 22. If the plates are moved directly toward each other without any relative horizontal motion parallel to their surfaces the spring 20 will be compressed as shown in FIGS. 7 and 8. The spring gradient will be the greatest and the allowable deflection the least in this method of application. If relative horizontal motion is permitted between the upper and lower plates 21 and 22 then motion of the two plates toward one another will result in compression of the spring as shown in FIGS. 3 and 4. This method of application provides a flatter gradient and greater allowable deflection. By a proper selection of wire diameter and coil diameter the spring can be made to produce a flat or even a negative gradient. This is due to the fact that the lengthening dimension L-l, L-2, L-3 results in a greater mechanical advantage of the compressing forces F-l, F-2, F-3 over the spring resistance and any sliding frictional resistance between the spring coils and the plates.v

It is obvious that at any stage of compression the two plates can be moved horizontally in relation to one another to produce a sliding or a rolling action as seen. Thus in FIGS. 1, 3, 5 and 7 the arrow 25 indicates a relative movement of the plates 21 and 22 in a direction longitudinal to the axis of the spiral of spring thereby providing a sliding motion while nevertheless the resilient resistance or compression is retained. Where the surfaces 21 and 22 are devices between which current is to be transferred, the spring 20 when made of an appropriate current carrying material such as beryllium copper will provide a multiplicity of contact points a, a, a on either side of the spring and against the opposite surfaces.

When the plates 21, 22 are moved in a direction transverse to the main axis of the spring 20 as shown .by the arrow 26 in FIGS. 2, 4, 6 and 8, then the spring will roll while nevertheless maintaining the same pressure resistance or resilience and the same plurality of contactpoints. This rolling action takes place even under the compression of FIGS. 7 and 8. This therefore permits the plates 21 and 22 and their surfaces which are in contact with the spring 20 to move with respect to each other while nevetheless maintaining an appropriate pressure relationship between them and especially while maintaining a good current carrying contact between them.

Thus the spring may be used in a buffer where a negative gradient or reducing resistance is desirable. It may be used in chuck mounting applications. It can be used as a shock dampening wheel or roller. It may be used for mechanical force where limited space is a problem. It may be especially used as an electrical current transfer means simultaneously with the above applications.

In FIG. 9 there is shown schematically the application of the novel spring arrangement between a moving conductor and terminal whereby appropriate pressure means is obtained between a moving conductor and the terminal while at the same time efficient current transfer is obtained. The moving conductor of this type may be used in connection with circuit breakers such as for instance for vacuum bottle circuit breakers of the type shown in application Ser. No. 282,319, filed Aug. 21, 1972, entitled Miniature High Voltage Circuit Breaker, and assigned to the assignee of the present invention.

The moving conductor shaft 101 is here shown as essentially a cylindrical member mounted in a terminal bearing 102 of the terminal 103. An appropriate actuator 104 is provided for the conductor 101. The terminal bearing 102 is provided with a clearance 105 between the bearing and the moving conductor shaft 101. L0- cated in this clearance is the novel pressure current transfer spring of the present invention and of the type previously described. The spring is retained in position in any appropriate manner as for instance by the collar 107 on the moving conductor and the inwardly extending lip 108 on the terminal so that the spring member cannot fall out and lose its connection. In this case the spring 120 is preferably of the form shown in FIG. 10 in which a spring of the type previously described in connection with the spring 20 of FIGS. 1 to 8 is arranged so that its longitudinal axis is spirally wound. The individual contact points of the turns of each of the coils of the spring in the spirally wound arrangement provide a plurality of contact points as already previously described and the number of contact points between the terminal and the moving conductor is simply a'function of the number of turns that are used in forming the spirally arranged coil spring 120.

An alternative embodiment also previously referred to is shown in FIG. 11 where instead ofa spiral of a coil spring 120 a plurality of coil springs 220 may be used as seen in FIG. 11. These are connected individual loops which may be used in place of the continuous spiral 120.

Where the individual loops 220, 220 are used as shown in FIG. 11 in place of the spirally arranged element 120 of FIG. 10 in the current transfer means of FIG. 9 then the tension of the spring will nevertheless hold the springs 220 on the conductor shaft 101 even when the conductor collar 107 moves to the dotted line position 107a. Alternatively the terminal bearing 102 of the terminal 103 may be made long enough so that as the moving conductor moves down in the bearing the collar 107 will never leave the lower end 112 of the terminal 103.

In the construction shown in FIG. 9 the moving conductor is always in contact with the terminal 103. In certain cases such as in disconnect contact arrangements also of a type shown in the aforesaid application Ser. No. 282,319 the moving contact is to be entirely withdrawn from the terminal. In this case as shown in FIG. 12 the moving conductor 201 is in currrent conducting relationship with the terminal 203 by means of either the spirally wound coil of coil springs 120 of FIG. 10 or the individual loops of coil springs 220 of FIG. 11. The bearing 202 of the terminal 203 is provided with an upper collar or retainer 208 to retain the spring elements 120 or 220 and also with a lower collar or retainer 207 thereby forming a recess in which the springs 120 or 220 are completely contained. It may thus be seen that the contact plug 201 may move from the solid line position 201 to the dotted line position 201a leaving the terminal entirely while the springs 120 or 220 are retained in position by the collars or lips 208, 207. The surface of the contact element 201 which first enters the terminal in FIG. 12 on reconnection of the contact with the terminal is appropriately beveled or chamfered at 215 in order to facilitate its entry into the spirally woundor looped coiled springs 120 or 220 of FIG. 12.

By this means therefore appropriate balancing pressure arrangement is maintained to centralize the moving contact plug 201 in the terminal while at the same time a multiplicity of current transfer points is obtained through the outer turns of the springs.

In FIG. 13 there is shown in perspective a spirally wound longitudinal coil 320 which may be utilized essentially in those applications where pressure resilience and resistance and current transfer between two plates which slide or roll with respect to each other may be used as shown schematically in FIGS. 1 to 8.

In the foregoing the present invention has been described solely in connection with preferred illustrative embodiments thereof. Since many modifications and variations of the present invention will now be obvious to those skilled in the art it is preferred that this disclosure be limited not by the specific illustrative embodiments herein contained but only by the appended claims.

The embodiments of the invention in which an exlusive privilege or property is claimed are defined as follows:

1. A resilient pressure device comprising a coil spring;

two members;

a surface of one of said members being spaced from and facing a surface of the other of said members; said coil spring being located between said surfaces; said coil spring being wound on an axis and comprising a plurality of connected turns of resilient material;

said axis extending substantially parallel to said surfaces;

the space between said surfaces being less than the diameter of said coil spring;

said surfaces compressing said coil spring in a direction transverse to the said axis thereof;

each of the turns of said coil spring presenting at least one pressure point against each surface.

2. The resilient pressure device of claim 1 wherein each of the said surfaces is an electrical current conducting element;

the coil spring is formed of electrical currrent conducting material;

the coil spring forming a current conductive structure between said current conducting elements and providing a plurality of contact points for each of said elements.

3. The resilient pressure device of claim 1 in which said members are slidable with respect to each other in a plane parallel to the axis of said coil spring while maintaining the said compression of said coil spring in a direction transverse to the axis thereof.

4. The resilient pressure device of claim 2 in which said members are slidable with respect to each other in a plane parallel to the axis of said coil spring while maintaining the said compression of said coil spring in a direction transverse to the axis thereof and while maintaining the current conducting connection be-. tween the members through said plurality of contact points of said coil spring.

5. The resilient pressure device of claim 3 wherein the said members are movable toward each other varying the pressure on the turns of said coil spring.

6. The resilient pressure device of claim 4 wherein the said members are movable toward each other varying the pressure on the turns of said coil spring while maintaining the current conducting connection between the members through said plurality of contact points of said coil spring.

7. The resilient pressure device of claim 1 wherein one of the members comprises a shaft and the other of the members comprises a beraing.

8. The resilient pressure device of claim 7 wherein said shaft is a conductor of electrical current and in which an electrical terminal is provided;

said shaft being movable with respect to said bearing said coil spring being of electrically conductive material and providing a plurality of contact points between the shaft and the bearing.

9. The resilient pressure device of claim 8 in which the axis of the coil spring is spirally wound between the shaft and the bearing.

10. The resilient pressure device of claim 8 in which a plurality of coil springs are provided between the shaft and bearing;

each spring being supported in the space between the faces of the shaft and bearing with its axis parallel to the facing elements.

11. The resilient pressure device of claim 8;

having a pair of retainers on said bearing, said retainers being spaced from each other, said spring being supported in said bearings between said retainers.

12. The resilient pressure device of claim 8 having a collar on said shaft and a retainer on said bearing spaced from said collar;

said spring being supported between said collar and said retainer. 

1. A resilient pressure device comprising a coil spring; two members; a surface of one of said members being spaced from and facing a surface of the other of said members; said coil spring being located between said surfaces; said coil spring being wound on an axis and comprising a plurality of connected turns of resilient material; said axis extending substantially parallel to said surfaces; the space between said surfaces being less than the diameter of said coil spring; said surfaces compressing said coil spring in a direction transverse to the said axis thereof; each of the turns of said coil spring presenting at least one pressure point against each surface.
 2. The resilient pressure device of claim 1 wherein each of the said surfaces is an electrical current conducting element; the coil spring is formed of electrical current conducting material; the coil spring forming a current conductive structure between said current conducting elements and providing a plurality of contact points for each of said elements.
 3. The resilient pressure device of claim 1 in which said members are slidable with respect to each other in a plane parallel to the axis of said coil spring while maintaining the said compression of said coil spring in a direction transverse to the axis thereof.
 4. The resilient pressure device of claim 2 in which said members are slidable with respect to each other in a plane parallel to the axis of said coil spring while maintaining the said compression of said coil spring in a direction transverse to the axis thereof and while maintaining the current conducting connection between the members through said plurality of contact points of said coil spring.
 5. The resilient pressure device of claim 3 wherein the said members are movable toward each other varying the pressure on the turns of said coil spring.
 6. The resilient pressure device of claim 4 wherein the said members are movable toward each other varying the pressure on the turns of said coil spring while maintaining the current conducting connection between the members through said plurality of contact points of said coil spring.
 7. The resilient pressure device of claim 1 wherein one of the members comprises a shaft and the other of the members comprises a bearing.
 8. The resilient pressure device of claim 7 wherein said shaft is a conductor of electrical current and in which an electrical terminal is provided; said shaft being movable with respect to said bearing said coil spring being of electrically conductive material and providing a plurality of contact points between the shaft and the bearing.
 9. The resilient pressure device of claim 8 in which the axis of the coil spring is spirally wound between the shaft and the bearing.
 10. The resilient pressure device of claim 8 in which a plurality of coil springs are provided between the shaft and bearing; each spring being supported in the space between the faces of the shaft and bearing with its axis parallel to the facing elements.
 11. The resilient pressure device of claim 8; having a pair of retainers on said bearing, said retainers being spaced from each other, said spring being supported in said bearings between said retainers.
 12. The resilient pressure device of claim 8 having a collar on said shaft and a retainer on said bearing spaced from said collar; said spring being supported between said collar and said retainer. 